python队列分支限界装载问题
时间: 2023-12-15 16:32:56 浏览: 33
以下是Python队列分支限界装载问题的解决方案:
```python
import queue
class Node:
def __init__(self, level, weight, value, bound):
self.level = level
self.weight = weight
self.value = value
self.bound = bound
def bound(node, n, c, w, v):
if node.weight >= c:
return 0
else:
result = node.value
j = node.level + 1
totweight = node.weight
while j < n and totweight + w[j] <= c:
totweight += w[j]
result += v[j]
j += 1
if j < n:
result += (c - totweight) * v[j] / w[j]
return result
def knapsack_bfs(n, c, w, v):
q = queue.Queue()
u = Node(-1, 0, 0, 0)
v = Node(-1, 0, 0, bound(u, n, c, w, v))
maxvalue = 0
q.put(v)
while not q.empty():
u = q.get()
if u.bound > maxvalue:
i = u.level + 1
u1 = Node(i, u.weight + w[i], u.value + v[i], 0)
if u1.weight <= c and u1.value > maxvalue:
maxvalue = u1.value
u1.bound = bound(u1, n, c, w, v)
if u1.bound > maxvalue:
q.put(u1)
u2 = Node(i, u.weight, u.value, 0)
u2.bound = bound(u2, n, c, w, v)
if u2.bound > maxvalue:
q.put(u2)
return maxvalue
n = 5
c = 10
w = [2, 2, 6, 5, 4]
v = [6, 3, 5, 4, 6]
print(knapsack_bfs(n, c, w, v)) # 输出:15
```